Cataract extraction is one of the most commonly performed surgical procedures in the world with estimated 2.5 million cases performed annually in the United States and 9.1 million cases worldwide in 2000. This was expected to increase to approximately 13.3 million estimated global cases in 2006. This market is composed of various segments including intraocular lenses for implantation, viscoelastic polymers to facilitate surgical maneuvers, disposable instrumentation including ultrasonic phacoemulsification tips, tubing, and various knives and forceps. Modern cataract surgery is typically performed using a technique termed phacoemulsification in which an ultrasonic tip with an associated water stream for cooling purposes is used to sculpt the relatively hard nucleus of the lens after performance of an opening in the anterior lens capsule termed anterior capsulotomy or more recently capsulorhexis. Following these steps as well as removal of residual softer lens cortex by aspiration methods without fragmentation, a synthetic foldable intraocular lens (IOLs) is inserted into the eye through a small incision.
Many cataract patients are astigmatic. Astigmatism can occur when the cornea has a different curvature one direction than the other. IOLs are not presently used to correct beyond 5D of astigmatism, even though many patients have more severe aberrations. Correcting it further often involves making the corneal shape more spherical, or at least more radially symmetrical. There have been numerous approaches, including Corneaplasty, Astigmatic Keratotomy (AK), Corneal Relaxing Incisions (CRI), and Limbal Relaxing Incisions (LRI). All are done using manual, mechanical incisions. Presently, astigmatism cannot easily or predictably be corrected fully using standard techniques and approaches. About one third of those who have surgery to correct the irregularity find that their eyes regress to a considerable degree and only a small improvement is noted. Another third of the patients find that the astigmatism has been significantly reduced but not fully corrected. The remaining third have the most encouraging results with most or all of the desired correction achieved.
What is needed are ophthalmic methods, techniques and apparatus to advance the standard of care of corneal shaping that may be associated with invasive cataract and other ophthalmic pathologies.